1. Field of the Invention
The present invention relates to a fuel injection control apparatus for controlling fuel to be injected into engines used in industrial vehicles and the like and, more particularly, to a fuel injection control apparatus for engines for controlling fuel injection at a startup time of the engines.
2. Description of Related Art
Conventionally, there have been proposed some control apparatus and methods for accurately controlling fuel to be supplied to engines of vehicles by controlling an injector (a fuel injection valve) to inject the fuel into an air-intake passage according to operating conditions of the engines.
Paying particular attention to a startup performance of the engines, there is an apparatus adopting a fuel injection control which is exercised at startup in proportion to engine cranking caused by a starter.
An example of such the fuel injection control apparatus is disclosed in Japanese patent unexamined publication No. SHO 58(1983)-41229. The control apparatus disclosed in the publication is arranged such that even if a driver carelessly depresses an accelerator pedal to demand acceleration during the startup (the cranking) of an engine, the amount of fuel to be injected at startup is not compensated to increase.
When the engine is started without depression of the accelerator pedal, the valve opening time of an injector is controlled to provide a predetermined air-fuel ratio based on outputs of an air-flowmeter and a crank angle sensor. Specifically, the fuel injection amount is controlled based on an air-intake amount detected by the air-flowmeter and a pulse signal output from the crank angle sensor which detects variations in rotational angle of a crankshaft. Even if a driver inadvertently depresses the accelerator pedal to demand acceleration during startup of the engine cranked by the starter which is in an ON state, a control operation circuit distinguishes that the engine is in the startup state based on an ON signal from a starter switch and cancels increase compensation of the fuel injection amount.
Meanwhile, the conventional fuel injection control mentioned above is arranged so that the increase compensation is not performed even if the accelerator pedal is pressed down during startup of the engine. As a result, the fuel would not be supplied in excess amounts, preventing deteriorations in startability of the engine. This fuel injection control is, however, performed based on the pulse signal indicative of the engine rotation speed detected by the crank angle sensor during the startup. If the pulse signal is not detected immediately after the start of cranking, the injector is not allowed to inject the fuel until a pulse signal is detected. Thus, the startup (or cranking) of the engine is delayed and a period of time needed for the startup is liable to become longer.
Although the startup time is prolonged, such the startup delay is considered as having little effect on driving operations of the vehicles using the engines which are cranked with an engine (ignition) key. On the other hand, if the above fuel injection control apparatus is adopted in the engines of industrial vehicles, such as a golf-cart, arranged such that cranking, traveling and stopping are performed in proportion to operations of the accelerator pedal, such the engine of the golf-cart would cause troubles at startup, for example, in a parked position (when stopping) on a slope.
Specifically, the golf-cart using a parking brake is constructed such that the parking brake is released when the accelerator pedal is depressed by a driver. When the accelerator pedal is depressed to start the engine of the cart parked on a slope, therefore, cranking of the engine is started simultaneously with depression of the accelerator pedal, while the parking brake is also released at the same time. At this time, if the startup of the engine is delayed after release of the parking brake as described above, the golf-cart on the slope is consequently liable to unexpectedly move under its own weight in correspondence with the startup delay, which may possibly give anxiety to the driver.
The present invention has been made in view of the above circumstances and has an object to overcome the above problems and to provide a fuel injection control apparatus for engines capable of preventing startup delay of the engines.
Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will become understood from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the purpose of the invention, there is provided a fuel injection control apparatus for engines, the apparatus being provided in an engine of which startup is assisted by a startup assist device and operation is controlled by operation control means, and being arranged to control fuel injection means to inject fuel to be supplied to the engine based on operating conditions of the engine, the apparatus including: startup injection control means for actuating the startup assist device and for causing the fuel injection means to perform initial injection when the operation control means is operated to start the engine.
According to the fuel injection control apparatus of the present invention, the initial injection is performed by means of the fuel injection means in substantial synchronism with the actuation of the startup assist device, so that the startup delay of the engine can be prevented, thus shortening the period of time needed for the startup of the engine.